Sorry to hear that you are dealing with strictures in your colon. I can commiserate-- I recently found that I have 3 very long strictures in my colon, and because of them, I cannot have a colonoscopy done either. But, like you, I have been feeling pretty good--I each pretty much whatever I want and am not in the bathroom very much.
The sad thing is that I met with a surgeon who said basically my only choice is to have my entire colon removed and get an ileostomy. They cannot removed just the strictured areas because I would only be left with less than half of a colon. I was pretty devastated, but have been reading/posting on the Ostomies Message Board here, and it really does not seem like that bad of a thing once you get used to the idea. Like you, my main concern is colon cancer (which they won't be able to catch early because I can't have a colonoscopy done...!)
The only good thing is that if/when I do get an ileostomy, I would pretty much be cured of my Crohn's, which only affects my colon/rectum area. But, I feel like I am so young for this to happen...I am only 26!
I hope Humira works for you!!!